Training & Nutrition - 170 to 172.5 Big Difference?

I just completed my Ultegra to Dura Ace upgrade. Yeaaaa! However, my first test ride was a surprise! After 30 miles my legs were toast! The last 20 miles were a struggle. I could barely climb some hills that I could almost negotiate while in my aero bars in the past!!
Is this difference common? Should I have been that tired, when normally I'm just warming up?
One thing I did not do was lower my seat 2.5 mm to compensate for the change, could this be the driver to the disappointing results of my test ride? My butt wasn't any sorer, so I don't think I was rocking on the seat. I do know that my legs were slightly more extended on the bottom strokes.

When I got my current bike, it had 172.5s. So, granted, a lot of stuff was changing, but the size and basic geometry were the same. I found that it took me quite a while to adapt. The change seems small, about a tenth of an inch, but it's a tenth shorter at the top, and a tenth lower at the bottom, so really it's closer to 1/4 inch overall. Also, 172.5s are longish for me, given my leg length. I suspect the difference isn't so much a conditioning thing as a relearning thing. Your legs have to get familiar with the change.

Originally posted by roadbuzz
When I got my current bike, it had 172.5s. So, granted, a lot of stuff was changing, but the size and basic geometry were the same. I found that it took me quite a while to adapt. The change seems small, about a tenth of an inch, but it's a tenth shorter at the top, and a tenth lower at the bottom, so really it's closer to 1/4 inch overall. Also, 172.5s are longish for me, given my leg length. I suspect the difference isn't so much a conditioning thing as a relearning thing. Your legs have to get familiar with the change.

It certainly was an unexpected eye opener to me! Thanks for the input, it definitly sounds logical. Hopefully my legs will get familiar with the new length soon.

My wife likes (that is spelled DEMANDS) 175's. Although she is only 5'6 she is long legged and can tell in a moment when I which cranks on her...the whinnnnnneeeee starts until she gets the 175's back. She might complain about gears, seat height, saddle, my income, all she know is IT AIN'T RIGHT!

It appears that crank length is more than it appears.

It may have just been a bad day..

Originally posted by fubar5
It may have just been a bad day..
Yeah, maybe, but as bad as my legs were toasted in such a short distance with relatively few hills was really out of the ordinary. I was shocked at how bad my legs burned on the simplest upgrades. Whew.

I have 175mm on my MTB, 170mm on my old road bike and 172.5 on my new road bike. I ride all 3 bikes on a weekly basis and I have never noticed any difference. It's only 2.5mm.

CHEERS.

Mark

You need to lower your saddle by 2.5mm and move it forward by 2.5mm, if "knee-over-pedal" is the position you prefer.

I have 175mm on my MTB, 170mm on my old road bike and 172.5 on my new road bike. I ride all 3 bikes on a weekly basis and I have never noticed any difference.

hey, that's exactly what i have... well, 170 on my road bike, 172.5 on my old MTB now commuter and 175 on my new MTB.

i must say that i really like the 175s and have been thinking about something longer for my road bike... although in general i think you don't want/need quite as long for the road, partly for clearance (road clearnce and tire/pedal clearance) but also b/c you don't need the leverage the same way as on a mountain bike...

but i've been thinking about it as i had never before considered crank-lenght and just rode whatever came on the bike.